implement sbrk() by calling hoard's version, through sbrk_hook (fct pointer was named this way in R5).

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@17540 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/system/libroot/posix/malloc/arch-specific.cpp

@@ -34,6 +34,8 @@
 #	define CTRACE(x) ;
 #endif
 
+extern "C" void *(*sbrk_hook)(long);
+void *(*sbrk_hook)(long) = &BPrivate::hoardSbrk;
 
 using namespace BPrivate;
 

src/system/libroot/posix/unistd/sbrk.c

@@ -7,10 +7,13 @@
 #include <unistd.h>
 #include <errno.h>
 
+/* in hoard wrapper */
+extern void *(*sbrk_hook)(long);
 
 void *
 sbrk(long increment)
 {
-	// this function is no longer supported
+	if (sbrk_hook)
+		return (*sbrk_hook)(increment);
 	return NULL;
 }